I picked up this Type 99 a bunch of years ago, mostly because it was offered to me for $50, and stuck it in a safe with a bunch of other project guns, where it sat for ages.
its missing the mag spring and follower, so its basically just a single shot for now.
Factory ammo is made still by PPU and maybe some others that I don’t know of, but none was available off the shelf near me (country Vic) so I looked into making my own. I have a great book called “The Manual of Cartridge Conversions” which is an awesome reference for anyone wanting to load and shoot obscure cartridges.
I scored a bag of once fire 30-06 brass and set to depriming it at which point I discovered there was some ex-mil berdan primed stuff in there
Joy!!! I next invested in a cheap ottoscope off ebay which I now use to check all second hand brass when I sort it.
Anyway back to my conversion. So after sorting and depriming my thirty-aught brass I set to it.
First step should probably have been to anneal the brass but I didn’t and it all seems to have worked out ok,
I ran the brass into the 7.7 jap seating die, with the seating plug removed. this starts to bump the shoulder back.
Next I roughly cut the brass to length 3 at a time with a hacksaw in a jig I made out of a scrap bit of pine
Before trimming them to the correct length in my case trimmer.
They can be done without the hacksawing but it sped it up heaps.
once trimmed to length the brass is full length resized in the Jap die and is then ready to be loaded.
this pic shows from R to L, a 30-06 case, case once run through the Jap seating die with the shoulder bumped back before trimming and a trimmed and FLS’d 7.7 Jap case, although the neck on this case is shorter than full speck factory brass as these pic’s were taken through out my trial and error work. they still work just fine for me.
finally some loaded ammo ready to be fired, next to an unmodified 30-06.
This is now my favourite milsurp and with 174gn 303 pills on a load of trail boss is a really accurate plinker and probably the best $50 I’ve ever spent, made more satisfying by shooting my own converted ammo!
I have done this also to convert 30-06 brass into 8mm Mauser and it works just the same.